I'm having some linker trouble on linux with my cmake project.
I've installed a package (nvidias Cg toolkit) which puts the library files in /usr/lib64
I use the find script here: http://code.google.com/p/nvidia-texture-tools/source/browse/branches/2.0/cmake/FindCg.cmake?r=452
If I print out CG_LIBRARY and CG_GL_LIBRARY with message() after running the find script they are both set to the correct file and path:
/usr/lib64/libCg.so-lpthread
/usr/lib64/libCgGL.so
The find script adds -lpthread to CG_LIBRARY. I've also tried removing the line where it adds this and add it manually to the target project.
Then I add these variables to the target project with target_link_libraries().
When I run make it says:
/usr/bin/ld: cannot find -lCg
/usr/bin/ld: cannot find -lCgGL
collect2: error: ld returned 1 exit status
Now if I run make with VERBOSE=1 I can see that there is no -L/usr/lib64 entry. If I edit the CMakeFiles/MyProject.dir/link.txt and add the entry manually it links it fine. Shouldn't cmake add the -L entries automaticaly with target_link_libraries()?
I've also tried using link_directories to add the -L manualy, but that doesn't do anything either..
Related
I've installed libcrypto++-dev and crypto1 besides their 32-bit versions ( since I think the program I'm trying to compile needs them). But still I get the following error :
/usr/bin/ld: Cannot find -lcrypto
Any suggestions ?
I use ubuntu 18.04
The linker would be unable to find something like libcrypto.so.1 based on the combo of default/configured and arg-based set of directories to search.
Most likely your lib resides in a dir outside of the linker's default list.
After identifying the lib install dir, replace /usr/local/lib64 within this example:
gcc <list-of-objects> -o xyz -L/usr/local/lib64 -lcrypto
I'm using the Visual C++ for Linux plugin. I can run a basic Hello world without problems. My actual project uses a .lib. It compiles fine but I get an error during linking (this is copied from Visual Studio's output pane):
ClCompile:
Starting remote build
Compiling sources:
Invoking g++
g++ -c -x c++ /home/devbox/projects/LinuxProgServ/LinuxProgServ/main.cpp -I /home/devbox/projects/LinuxProgServ/include/libuv -I /home/devbox/projects/LinuxProgServ/../include/lubuntu -I "/home/devbox/projects/LinuxProgServ/../include/lubuntu/x86_64-linux-gnu" -g2 -gdwarf-2 -o "/home/devbox/projects/LinuxProgServ/obj/x64/Debug/main.o" -Wall -Wswitch -W"no-deprecated-declarations" -W"empty-body" -Wconversion -W"return-type" -Wparentheses -W"no-format" -Wuninitialized -W"unreachable-code" -W"unused-function" -W"unused-value" -W"unused-variable" -O0 -fno-strict-aliasing -fno-omit-frame-pointer -fthreadsafe-statics -fexceptions -frtti -std=c++11
main.cpp
Done compiling '/home/devbox/projects/LinuxProgServ/LinuxProgServ/main.cpp'
Link:
Linking objects
Invoking ld
g++ -o "/home/devbox/projects/LinuxProgServ/bin/x64/Debug/LinuxProgServ.out" -Wl,--no-undefined /home/devbox/projects/LinuxProgServ/obj/x64/Debug/main.o -llibuv.lib
/usr/bin/ld: cannot find -llibuv.lib
collect2: error: ld returned 1 exit status
libuv.lib is specified in Project Properties>Linker>Input>Library Dependencies. I tried the following without success:
Copy the lib to /home/devbox/projects/lib and add that directory to
the linker command with -L, both using Visual Studio's additional
library folder field and directly in the Additional command line
options field. This results in the same final command.
Copy the lib to the output directory and set it to be copied
Add the local Windows path to Visual Studio's additional library folders
Add the linux path from #1 to Visual Studio's additional library folders
Try with another library
I made the same project but for Windows just to be sure and it works.
Am I missing something? Obviously I could just run the commands myself or use any variant of *make but that's not the point.
When you pass a library to g++ with -l, g++ helpfully prefixes the name you give with lib then looks for a file of that name with a .so or .a extension on the library search path. By convention, shared libraries (dlls) have the .so extension and static libraries the .a extension.
The route of least resistance would be to build your library with the .a extension, i.e. libuv.a then specify it to the VCLinux project library dependencies as uv. And specify the library search path with -L, as you do in your step 1.
Alternatively, you can put the full path of the library on the g++ link command line, without -l prefix, i.e. /home/devbox/projects/lib/libuv.lib and g++ will use it in the same way it uses other object files. Set via Linker/All Options/Additional Options.
Update: on reflection, this second approach won't work. Although g++ (gcc) will accept the library as an input when specified with its fully qualified path, the library must appear after the program object files for references to be resolved. Unfortunately there is no control over positioning of Additional Options in VCLinux which always puts them at the front of the parameter list on the g++ command line, i.e. before the object file(s). :(
And, at the risk of stating the obvious, the library must be built on Linux with g++ and be located on a path visible to g++ when linking your program.
I am getting this error when i compile my test file in linux centOS7.
/usr/bin/ld : cannot find -lgcc_s
collect2: error: ld return 1 exit status
It means, it's not finding an existing library gcc_s.
One reason for this, this is because although libgcc is present, it may not be not in the paths known to ldconfig.
try this by doing
sudo /sbin/ldconfig -p | grep libgcc
if the output show that the is link to libgcc corresponds to paths that you have listed above?
A workaround for you may be to add the link to the relevant library to your compile command, for example, it will do the job.
g++ yourprogram.cpp -L /usr/lib/gcc/x86_64-linux-gnu/4.6/
I would like to install the nccmp program to compare netCDF files.
Checking the documentation, the installation follows the typical structure:
./configure
make
make check
make install
make clean
However, I'm stuck in the first step because the configure is not able to find my netCDF libraries. But I don't know why.
My libs are not in the default folder, I've installed them in /opt. But I've included the path of the netCDF libs in my LD_LIBRARY_PATH variable.
I tried also to create a link in the default lib folder to my netCDF libs
ln /opt/netcdf-4.2.1.1/lib/libnetcdf.so /usr/lib/libnetcdf.so
ln /opt/netcdf-4.2.1.1/lib/libnetcdff.so /usr/lib/libnetcdff.so
ln /opt/netcdf-4.2.1.1/lib/libnetcdf.a /usr/lib/libnetcdf.a
ln /opt/netcdf-4.2.1.1/lib/libnetcdff.a /usr/lib/libnetcdff.a
But it doesn't work either. I explicitly used the path in the call
./configure --libdir=/opt/netCDF/
I set LIBS and LDFLAGS to
LDFLAGS=-L/opt/netcdf-4.2.1.1/lib/
LIBS=/opt/netcdf-4.2.1.1/lib/
and execute configure then, but with the same bad results:
checking for nc_open in -lnetcdf... no
configure: error: in `/opt/nccmp':
configure: error: Required NetCDF library not found!
In the config.log I see:
configure:3763: gcc -o conftest -g -O2 conftest.c -lnetcdf -lm >&5
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../../lib/libnetcdf.a(libnetcdf4_la-nc4file.o): In function nc4_rec_read_types':
/opt/NETCDF_BUILD/netcdf-4.2.1.1/libsrc4/nc4file.c:1850: undefined reference toH5Gget_create_plist'
and many more similar lines like that one...
I don't know what else to try, so any help would be really appreciated.
Thanks.
I already found the problem... I needed, as expected, to define LDFLAGS and CFLAGS in my shell and export them to allow the access of configure to those variables.
I have downloaded the latest GLUI source code and now I am trying to compile it. When I do so, I get the following error:
g++ -O0 -Wall -pedantic -I./ -I./include -I/usr/X11R6/include -o bin/example1 example/example1.cpp -L./lib -lglui -L/usr/X11R6/lib/libXdmcp.a -lglut -lGLU -lGL -lXmu -lXext -lX11 -lXi -lm
/usr/bin/ld: cannot find -lXmu
collect2: ld returned 1 exit status
When I did a locate libXmu, I get the following output:
> %:~/src/GLUI/src$ locate libXmu
> /usr/lib/libXmu.so.6
> /usr/lib/libXmu.so.6.2.0
> /usr/lib/libXmuu.so.1
> /usr/lib/libXmuu.so.1.0.0
Do I get the error because I don't have a /usr/lib/libXmu.so? If this is the case, how can I make one? (I am not experienced with linking at all).
Thanks!
Linux distributions usually package the libraries needed for running programs separately from the files needed to build programs.
Look for packages named *-devel or *-dev.
I don't know which one you need in particular for this, but you can use apt-cache search to look for it.
The answer was actually one of the first ones here originally but the owner deleted it, it seems. I was able to solve the problem by creating a symbolic link to the latest version of the library (i.e. /usr/lib/libXmu.so.6) and compile the code successfully.
I had the same problem, if creating a symbolic link doesnt help,
try the following:
Print your $PATH ("echo $PATH"),
and check if the library file you need is in one of those directories.
Use "export PATH=/newly/added/path:$PATH" to add new directory to check.
Ive been including libevent, added "-levent" in the gcc command, and ld used file /usr/lib/libevent.so, so it looks like the "lib" prefix and extension are being added automatically by ld.
Keep it up.